Safety mechanism for automatic machines



F. W. BRAUN ETAL -SAFETY MECHANISM FOR AUTOMATIC MACHINES 4 sheets-sheet 1 BY ALFRED BRAUN ATTORI; s

June 1s, 1,959

Filed nea.` 2, 1957 June 16, 1959 F. w. BRAUN Erm.

SAFETY MECHANISM FOR AUTOMATIC MACHINES 4 Sheets-Sheet 2 Filed DeG. 2, 1957 Y ALFRED BRAUN ATTORN S F. W. BRAUN ETAL SAFETY MECHANISM FOR AUTOMATIC MACHINES June 16, 195.9

Filed Deo. 2, 1957 4 Sheets-Sheet 3 INVENTORS FREDERICK w.BRAuN n 1 ATTORNEYS June 16, 1959 F, w BRALJN ETAL 2,890,778

SAFETY MECHAISM FOR AUroA/IATIC` MACHINES 4 sheets-Sheet 4 Fled Dec. 2, 1957 INVENTORS FREDERICK W BRAUN BY ALFRED BRAUN MQ ATTORNEYS SAFETY MECHANHSM FOR AUTOIVIATIC MACHINES Frederick W. Braun, Dearborn, and Alfred Braun, Birmingham, Mich.

Application December '2, 1957, Serial No. 699,968

'7 Claims. (Cl. 192-1Z5) This invention-relates generally to safety devices for automatic machines wherein reciprocating punches are employed, such for example as automatic presses wherein a die and a reciprocating punch'are utilized for formingy articles, such as stop light switch housings (herein referred to as the work), from metal blanks by a cold extrusion process, and refers more particularly to mechanism for automatically stopping the operation of the -machne in the event the work being formed or shaped should stick to the punch on the upstroke thereof.

One of the essential objects of the invention is to provide a safety mechanism of the type mentioned that includes means, preferably in the form of a swinging member, that can swing freely in opposite directions past the lower end of the punch when the latter is free of the work; but will abut and will be stopped by any work stuck to the punch.

Another object is to provide a safety mechanism including means, preferably in the form of aplunger, that may reciprocate freely within a predetermined normal range relative to an electric switch controlling the operation of the machine when the swinging member is swinging freely as aforesaid; but is movable beyond'said normal range to contact and actuate said electric switch and thereby cause the operation of the machine to be stopped ywhen said swinging member abuts and is stopped by work stuck to said punch. f

Another object is to provide a safety mechanism including means, preferably in the form of a pivotally mounted member, that is carried by and movable with the ram of the machine in abutting relation with the plunger and is operatively connected to the swinging member, whereby said pivotally mounted member will permit the plunger to remain within said normal range out of contact with said electric switch when the swinging member is swinging freely; but will move the plunger beyond said normal range into contact with the electric switch to stop operation of the machine when the swinging member abuts and is stopped by work stuck to the punch.

Another object is to provide a safety mechanism wherein a spring is operable during the upstroke of the punch when such punch is free of work to retain the plunger within said normal range out of contact with said electric witch, and to cause said plunger to move the pivotally mounted member downwardly about its pivot and thereby cause the swinging member to swing in one direction past the lower end of the punch, for example from rear to front thereof; but is yieldable when .the swinging member abuts and is stopped by work stuck to said punch to permit the pivotally mounted member to move the plunger beyond said normal range to contact and actuate the electric switch and thereby stop operation of the machine.

" Another object is to provide a safety mechanism where- 2,390,178 Patented .lune 16, 1959 in another spring, preferably carried by a shoe fixed to the ram, is operable during the downstroke of the punch, after the pivotally mounted member is relieved of the spring actuated plunger, to move the pivotally mounted member upwardly about its pivot and thereby cause the swinging member to swing in the opposite direction past the lower end of the punch,ifor example from front to rear thereof; but is yieldable during the upstroke of the punch when the pivotally mounted member abuts the spring actuated plunger to permit the pivotally mounted member to be moved downwardly about its pivot as aforesaid.

Another object is to provide a safety mechanism that is simple in construction, economical to manufacture, and efcient in operation.

Other objects, advantages and novel detailsY of construction of this invention will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings wherein:

Figure l is a top plan view of safety mechanism embodying our invention applied to a portion of a stationary frame ofthe machine, and showing by dotted lines the ram and shoe of the machine.

Figure 2 is a front elevation of the safety mechanism aforesaid, and showing by dotted lines the ram, shoe, retainer ring, punch retainer and punch of the machine, with the work stuck to the lower end of the punch in positionto be engaged by the swinging member of the safety mechanism.

Figure 3 is a side elevational View of the safety mechanism, showing by dotted lines the ram, shoe, retainer ring, punch retainer and punch of the machine in an intermediate position during the upstroke thereof, when the punch is free of the work, and showing by full lines the plunger in the lowermost position of the predetermined range lin which it normally reciprocates without contacting the electric switch.

Figure 4 is an end view of the supporting channel, and showing a portion of the spring pressed plunger carried thereby.

Figure 5 is a view similar to Figure 3, with the electric switch omitted, showing by dotted lines the ram, shoe, retainer ring, punch retainer and punch of ,the machine in an intermediate position during the upstroke thereof, with the work stuck to the lower end of the punch and engaged by the swinging member of the safety mechanism, and showing by full lines the plunger in its uppermost position beyond the predetermined range mentioned for operating contact with the push button of the electric switch.

Figure 6 is a side elevational view of the safety mechanism, showing by dotted lines the ram, shoe, retainer ring, punch retainer and punch of the machine in their lowermost position at the completion of the downstroke thereof, when the work has been formed in the die from the blank, and showing by full lines the lower end of the plunger in the lowermost position of the predetermined range in which it normally reciprocates.

' Figure 7 is an enlarged fragmentary sectional view through the die and showing the blank in the die in position to be engaged by the punch.

In the drawings A is a vertically reciprocating ram of an automatic press, B is a shoe fixed to the underside of said ram, C is a ring xed to the underside of said shoe, D is a punch retainer removably anchored within said ring, and E is a punch removably anchored within said retainer and engageable with a metal blank'F within a suitable upwardly opening die H to form/the Work.

l is a stationary frame of the automatic press, J is a block rigidly secured to one side of said frame, and K is a horizontally extending outwardly opening channel having the back thereof rigidly secured to said block J.

L and M respectively are blocks beyond opposite sides of said ring C and rigidly secured to the underside of said shoe B, and O is a U-shaped swinging member having laterally projecting supporting arms 11 and 12 respectively that are mounted to turn in said blocks L and M.

13 is a crank portion of the supporting arm 12 movable within a recess 14 in the block M, P is a block rigidly secured -to the underside of the ram A, Q is a pivotally mounted member, preferably in the form of a vertical plate, engaging a vertical slot 15 within said block P and suspended from a horizontal pivot pin 16 extending transversely of said block P adjacent the outer end thereof, and R is a connecting rod having one end rotatably clamped upon the crank portion 13 of the supporting arm 12 of the U-shaped swinging member O and having at its other end an adjustable clevis 17 that straddles and is pivotally connected to said pivotally mounted member Q adjacent the lower end thereof.

18 is a rod extending vertically through and adapted to be reciprocated in vertically spaced holes in the parallel horizontal anges 19 and 20 respectively of the channel K, 21 is a sleeve fixed to said rod 18 and movable vertically through the hole in the lower horizontal flange of the channel, 22 is a ange on the sleeve 21 at .the upper end thereof, 23 is a coil spring sleeved on the rod' 18 between Vthe ange 22 and the upper horizontal ange 19 of the channel K and urging the rod 18 and ,sleeve 21 downwardly, 23a is an ladjustable nut on said rod 18 and engageable vw'th the upper horizontal flange 19 of the channel K to limit downward movement of the rod 18 and sleeve 21, 24 is a clevis adjustably connected to the lower end of the rod 18, and 2S is a roller carried by the clevis 24 at the lower end thereof in the path of and adapted to be abutted by the upper end 26 of the pivotally mounted member Q.

In the present instance, the rod 18, sleeve 21, clevis 24 and roller 25 collectively constitute a plunger S and hereinafter such term will be used.

27 is a coil spring within a socket 28 in the shoe B S and slidably engaging said guide pin 31.

T is an electric switch in circuit with the usual controlsy (not shown) for operating the ram A of the machine and having a push button actuator 33 in the path of and adapted to be engaged by the upper end of the plunger S when the latter is moved upwardly beyond the predetermined range in which it normally reciprocates. 4Preferably the electric switch T has Ia. mounting plate 34 that is bolted to a block J rigidly secured to one side of the stationary frame I of the automatic press.

W is the work that is formed or shaped in the die H during the downstroke of the reciprocating punch E. As above stated, the work W is a stop light switch housing, and is formed from a metal blank F by a cold extrusion process. However, it is to be understood that the present invention is not limited to machines for mak- 4 of one inch, out of contact with the electric switch T.

During the upstroke of the punch E, when it is free of work, the pivotally mounted member Q will be carried upwardly by the ram A and will abut the roller 25 at the lower end of the plunger S. When this occurs the pivotally mounted member Q will be moved downwardly far enough about its pivot 16 by the resistance exerted by the spring pressed plunger S to cause the swinging member O to be swung by the connecting rod R in one direction past the lower end of the punch E, for example from rear to front thereof. Then, during further or continued upward movement of the ram A, the pivotally mounted member Q will be carfried upwardly by said ram A and will move the plunger S upwardly 5/5 of one inch to the uppermost position of the predetermined range mentioned, wherein the plunger S will be in spaced relation to and out of contact with the electric switch T. Hence the operation of the machine will not be stopped.

During the downstroke of the punch E, the spring 27 is operable, after the pivotally mounted member Q is relieved of the springpressed plunger S, to move the pivotally mounted member Q upwardly about its pivot 16 and thereby cause the U-shaped swinging member O to swing in the opposite direction past the lower end of the punch, for example from front to rear thereof.

However, should any work W stick to the punch E on the upstroke thereof, then the swinging member O will abut and will be stopped by the work W stuck to the punch E, instead of swinging past the lower end of the punch E. This will stop the downwardly moving pivotally mounted member Q in an abnormally raised or elevated position. Then, during further or continued upward movement of -the ram A, the pivotally mounted member Q will be carried upwardly by said ram A and will move the stuck to the punch E may then be removed safely by hand,

so that the operation of the machine may thereafter be resumed, as desired.

What we claim as our invention is:

1. Safety mechanism for an automatic machine having a vertically movable ram, means for forming an article from a metal blank including a punch carried by said ram, and an electric switch having an actuator and adapted to control the operation of said machine; comprising a plunger adapted to reciprocate within a predetermined range out of contact with the actuator of said electric switch, a swinging member carried by said ram and movable in opposite directions across the path of said punch but engageable with a formed article stuck to said punch, a pivotally mounted member carried by said ram and operatively connected to said swinging member, said pivotally mounted member being in the path of and adapted to abut said plunger during the upstroke of said ram,

. spring means urging said plunger toward said pivotally said pivotally mounted member toward said plunger,

ing stop light switch housings by such a process. Actually the invention is applicable to any automatic machine or press wherein a reciprocating punch is employed.

In use, when the punch E is moving up and down and is free of the work W the U-shaped member O can swing freely in opposite directions past the lower end of v said punch E. When the U-shaped member O is swinging freely as described, the plunger S may also reciprocate freely within a predeterminedrange, preferably 5A;

whereby said pivotally mounted member is operable during the downstroke of said ram when relieved of said spring urged plunger to cause the swinging member to swing in the opposite direction relative to said punch, said pivotally mounted member ybeing operable when said swinging member engages a formed article stuck to said punch during the upstroke of said ram to move said plunger againstpthe tension of the rst mentioned spring means beyond said predetermined range into operating contact with the actuator of said electric switch.

2. Safety mechanism for an automatic machine having a vertically movable ram, means for formingan article from a Iblank including a punch carried by said ram, and an electric switch having an actuator and adapted to control the operation of said machine; comprising a swinging member carried by said ram and normally movable in opposite directions across the path of said punch but engageable with a formed article/stuck to said punch, meansoperable during the downstroke. of said ram for swinging said member in one direction'relative to said punch, including a spring pressed pivotally mounted element carried by said ram, and means operable during the upstroke of said ram for swinging said member in the opposite direction relative to said punch, including a spring pressed plunger in the path of and adapted to actuate said pivotally mounted element, said plunger extending toward and normally being adapted to reciprocate 'within a predetermined range out of contact with the actuator of said electric switch, but movable against the tension of its spring by said pivotally mounted element beyond said predetermined range into operating contact with the actuator of said electric switch when said swinging member engages a formed article stuck to said punch during the upstroke of said ram.

3. Safety mechanism for an automatic machine having a vertically movable ram, means for forming an article from a blank including a punch carried by said ram, and an electric switch having an actuator and adapted to control the operation of said machine; comprising a member carried by said ram and normally movable in opposite directions across the path of said punch but engageable with a formed article stuck to said punch, means operable during the downstroke of said ram for moving said member in one direction relative to said punch, including a spring pressed element carnied by said ram, and means operable during the upstroke of said ram for moving said member in the opposite direction relative to said punch, including a spring pressed element in the path of and adapted to actuate the rst mentioned spring pressed element, the last mentioned spring pressed element extending toward and normally 'being movable within a predetermined range out of contact with the actuator of said electric switch, but movable against the tension of its spring by the iirst mentioned spring pressed element beyond said predetermined range into operating contact with the actuator of said electric switch when said movable member engages a formed article stuck to said punch during the upstroke of said ram.

4. Safety mechanism for an automatic machine having a vertically movable ram, means for forming an article from a blank including a punch carried by said ram, and an electric switch having an actuator and adapted to control the operation of said machine; comprising a mernlber carried by said ram and normally movable in opposite directions across the path of said punch but engageable with a formed article stuck to said punch, means operable during the downstroke of said ram for moving said member in one direction relative to said punch, including movable means carried by said ram, and means operable during the upstroke of said ram for moving said member in the opposite direction relative to said punch, including means in the path of and adapted to actuate the movable means carried by said ram, the last mentioned means extending toward and normally being movable within a predetermined range out of contact with the actuator of said electric switch, but movable by the movable means carried by said ram beyond said predetermined range into operating contact with the actuator of said electric switch when said movable member engages a formed article stuck to said punch during the upstroke of said ram.

5. Safety mechanism for an automatic machine having a vertically movable ram, means for forming an article from a blank including a punch carried by said ram, and an electric switch having an actuator` and adapted to control the operation of said machine; comprising a member Carried by said ram and normally movable in opposite directions across the path ofv said punch but engageable with a formed' article stuck to said punch, means operable during the dolwnstroke of said ram for moving said member in one direction relative to said punch, including a spring pressed pivotally mounted element carriedby said ram, and a connecting rod extending between and terminally connected to said movable member and said pivotally mounted element, a stationary support between said pivotally mounted element and said electric switch, and means operable during the upstroke of said ram for moving said member in the opposite direction relative to said punch, including a spring pressed plunger carried by said stationary support in the path of and adapted to actuate said pivotally mounted element, said plunger extending toward and normally being adapted 'to reciprocate within a predetermined range out of contact with the actuator of said electric switch, but movable against the tension of its spring by said pivotally mounted element beyond said predetermined range into operating contact with the actuator of said electric switch when said movable member engages a formed anticle stuck to said punch during the upstroke of said ram.

6. Safety mechanism for an automatic machine having a vertically movable ram, means for forming an article from a blank including a punch carried by said ram, and an electric switch having an actuator and adapted to control the operation of said machine; comprising a member carried by said ram and normally movable in opposite directions across the path of said punch but engageable with a formed article stuck to said punch, means operable during the downstroke of said ram for moving said member in one direction relative to said punch, including a spring pressed element carried by said ram, and a connecting rod extending between and terminally connected to said movable member and said spring pressed element, a stationary support between said spring pressed element and said electric switch, and means operable during the upstroke of said ram for moving said member in the opposite direction relative -to said punch, including a `spring pressed element carried by said stationary support in the path of and adapted to actuate the iirst mentioned spring pressed element, the last mentioned spring pressed element extending toward and normally being movable within a predetermined range out of contact with the actuator of said electric switch, but movable against the tension of its spring by the rst mentioned spring pressed element beyond said predetermined range into operating contact `with the actuator of said electric switch when said movable member engages a formed article stuck to said punch during the upstroke of said ram.

7. Safety mechanism for an automatic machine having a vertically movable ram, means for forming an article from a metal blank including a punch carried by said ram, and electric switch having an actuator and adapted to control the operation of said machine; comprising a plunger adapted to normally reciprocate within a predetermined range yout of contact with the actuator of said electric switch, a swinging member carried by said ram and normally movable in opposite directions across the path of said punch, but engageable with a formed article stuck to said punch, a pivotally mounted member carried by said ram and operatively connected to said swinging member, said pivotally mounted member being in the path of and adapted to abut said plunger during the upstroke of said rarn, a spring urging said plunger toward said pivotally mounted member and operable when said pivotally mounted member abuts said plunger to cause said swinging member to swing in one direction relative to said punch, said spring normally resisting movement of said plunger toward said electric switch, said pivotally mounted member being operable when said swinging member engages a formed article stuck to said punch during the upstroke of said ram to move said plunger against the tension of said spring beyond said References Cited in the file' of this patent UNITED STATES PATENTS Lynch Nov. 18, 1930 Prussng Feb. 2, 1932 'ONeail Aug. 12, 1947 Meyers Aug. 25, 1953 Bohaboy et al. -2 Oct. 13, 1953 

